Magnetooptic recorders sense information magneto-optically recorded on an optical disk by detecting the rotations of the linear polarization of light, such as caused by the well-known Kerr effect. The servo mechanisms for focusing track following and seeking for such magnetooptic recorders still employ the intensity-modulated reflected light caused by focus differences and track-following or track-seeking differences. It is desired to provide a better signal-to-noise ratio of the intensity-modulation portion of the reflected light beam for enhancing focus and tracking servo operations.